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强碱阴离子交换树脂催化合成假紫罗兰酮 总被引:5,自引:0,他引:5
本文报导使用国产强碱201×7(711-OH)型阴离子交换树脂作催化剂,在氮气中和56℃下催化柠檬醛与丙酮缩合合成假紫罗兰酮,产率为80.17%,纯度97.5%。研究了温度、溶剂及柠檬醛、丙酮不同用量对缩合反应的影响。 相似文献
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在SmI_3作用下和中性室温的条件下,环戊酮能与醛缩合,得到几乎定量产率的α,α'-二亚苄基环戊酮;但对环已酮,产率仅在20%左右。 相似文献
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微波促进下N,N-二甲基甲酰胺中的Knoevenagel反应 总被引:2,自引:0,他引:2
在微波促进下,芳醛与丙二腈或氰基乙酸乙酯在DMF中进行Knoevenagel缩合反应,以77%~98%的产率生成相应E-式烯烃。 相似文献
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报道了一种简便、有效的水相噤呐偶合反应。在含有少量季铵盐或季磷盐的氯化铵水溶液中.用金属锌促进羰基化合物进行水相噘呐偶合反应,其中加入的少量季铵盐或季磷盐有助于显著提高反应产率,噘呐醇产率由53%提高到87%。但噘呐偶合反应的产率受羰基周围环境的立体位阻影响较大,在此条件下,金属锌可有效地促进芳香族醛化合物进行水相噘呐偶合反应,得到产率较高的噘呐醇,但非对映异构体选择性差,而脂肪族醛化合物得到的噘呐醇产率较低,在同样条件下,酮类化合物不能顺利进行噘呐偶合反应。 相似文献
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本文利用相转移催化反应由脂肪族醛或酮、氯仿和氨合成了九个脂肪族α-氨基酸,产率21.4—52.4%。直链脂肪醛也能起反应。付产物α-氨基酰胺的离析,为环氧化物中间体历程提供了新的证据。 相似文献
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Lyu Fuyan Qu Yuanyuan Zhang Ningxiao Gao Jie Hao Xuedi Wu Miao 《Journal of Dispersion Science and Technology》2016,37(11):1563-1569
Yield stress is a key rheological parameter of dense paste. Considering practical utility and to estimate the possible slipping flow, yield stress measurements were carried out using the curve extrapolation method and vane method with rheometer in both controlled shear stress (CSS) and controlled shear rate (CSR) model. All measured yield stresses show to increase exponentially with concentration in different scale. The vane method yield stresses are both higher than the extrapolation curve yield stress. For the coal slurry used in this paper, the extrapolation curve yield stress is lower by 17–30% than the dynamic yield stress that obtained under test model CSR. It indicates that wall slip exists in pipeline transportation; meanwhile wall slip can reduce transportation resistance of dense paste to some extent. 相似文献
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两种甲醇水蒸气重整制氢催化剂的研究 总被引:1,自引:3,他引:1
对采用共沉淀法制备的CuZnAlO类铜系催化剂和采用水滑石类层柱材料(LDHs)前驱体制备的催化剂在甲醇水蒸气重整制氢反应中的性能进行了研究。对共沉淀法制备的CuZnAlO类铜系催化剂考察了ZrO2助剂的加入对催化剂反应性能的影响,发现Zr的质量分数为10%的催化剂显著提高CuZnAlO催化剂的反应性能。该催化剂的最佳反应条件:0.1 MPa、250 ℃、H2O/MeOH摩尔比1.0~1.3、3.56 h-1。在此反应条件下进行了COPZr2催化剂150 h稳定性实验。结果表明,该催化剂具有很好的反应稳定性。甲醇转化率和氢产率分别约为88%和83%,产物湿基组成中H2和CO的质量分数分别为>63%和0.20%~0.31%。对LDHs前驱体制备的催化剂,进行了70 h反应稳定性实验,结果表明,催化剂虽具有较高的起始活性,但随反应进行,活性有所下降,30?h后基本保持稳定,甲醇转化率和产氢率分别为73%和66%,产物湿基组成中H2和CO的质量分数分别为>55%和0.07%~0.08%。该类催化剂的反应稳定性虽较差,但却可以显著降低产物湿基组成中CO的摩尔分数。对LDHs前驱体制备的催化剂进行XRD和SEM表征结果表明,ZrO2的加入使催化剂中CuO晶粒分散更为均匀,颗粒更细。 相似文献
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采用固相-液相两步法合成一种天然抗菌环肽Thermoactinoamide A。在9-芴甲氧羰基(Fmoc)固相合成的基础上,通过优化N,N-二异丙基乙胺(DIPEA)的添加量,得到直链肽,收率为84%,在此基础上,采用液相环合的方法对直链肽进行环合,通过优化环合体系中混合液的配比、初始pH等条件,得到Thermoactinomide A,收率为51%,总收率43%。抑菌实验结果表明,Thermoactinoamide A对金黄色葡萄球菌的最小抑菌浓度为32μg/m L。固相合成与液相环合两步法合成步骤少、过程简单、产率较高,为进一步研究该天然产物的生物活性及构效关系奠定了基础。 相似文献
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半合成青霉素侧链合成的研究:Ⅹ.DL—5—(4—羟基苯基)海因的合成 总被引:2,自引:0,他引:2
以乙醛酸、尿素、苯酚为主要原料,在少量醇的存在下,于强酸性介质中经缩合反应合成了DL-5-(4-羟基苯基)海因。采用正交设计试验,找出了影响收率的主要因素,确定了最佳反应条件。醇的加入使产物收率提高到78.7%。 相似文献
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DAI Han-Song QIU Fa-Li LU Shao-JieChengdu Institute of Organic Chemistry Academia Sinica Chengdu Sichuan 《天然气化学杂志》1995,(3)
Ketone was the optimum sensitizer selected from many additives. With ketonc as the additive, the yield of formaldehyde was more than 2.40% and the highest yield Was 3.58% over the silica gel-1 catalyst, and remained almost unchanged during the catalyst life test of 500 h. Ketone can compensate the catalyst for the -OH loss shown by 1R, TGA and XPS of the catalysts before and after the reaction. 相似文献
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Murata N Fujimori S Ichihara Y Sato Y Yamaji T Tsuboi H Uchida M Suzuki H Yamada M Oikawa T Nemoto H Nobuhiro J Choshi T Hibino S 《Chemical & pharmaceutical bulletin》2006,54(11):1567-1570
We synthesized 9alpha-fluoromedroxyprogesterone acetate (FMPA) in order to test whether it is a more potent anti-angiogenic agent than medroxyprogesterone acetate (MPA), which has been widely used as a therapeutic agent for breast and endometrium cancers. FMPA was previously synthesized in 10 steps (total yield: 1%). An efficient synthesis of FMPA has been achieved in 6 steps (total yield: 12%). We examined the anti-tumor effect of FMPA, complexed with dimethyl-beta-cyclodextrin (DM-beta-CyD), on rat mammary carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA). FMPA showed great anti-tumor effect on DMBA-induced rat mammary carcinomas. 相似文献
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D-Lactic acid was synthesized by the fermentation of rice starch using microorganisms. Two species: Lactobacillus delbrueckii and Sporolactobacillus inulinus were found to be active in producing D-lactic acid of high optical purity after an intensive screening test for D-lactic acid bacteria using glucose as substrate. Rice powder used as the starch source was hydrolyzed with a combination of enzymes: alpha-amylase, beta-amylase, and pullulanase to obtain rice saccharificate consisting of maltose as the main component. Its average gross yield was 82.5%. Of the discovered D-lactic acid bacteria, only Lactobacillus delbrueckii could ferment both maltose and the rice saccharificate. After optimizing the fermentation of the rice saccharificate using this bacterium, pilot scale fermentation was conducted to convert the rice saccharificate into D-lactic acid with a D-content higher than 97.5% in a yield of 70%. With this yield, the total yield of D-lactic acid from brown rice was estimated to be 47%, which is almost equal to the L-lactic acid yield from corn. The efficient synthesis of D-lactic acid can open a way to the large scale application of high-melting poly(lactic acid) that is a stereocomplex of poly(L-lactide) and poly(D-lactide). Schematic representation of the production of D-lactic acid starting from brown rice as described here. 相似文献
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Pretreatment of corn stover by soaking in aqueous ammonia 总被引:1,自引:0,他引:1
Soaking in aqueous ammonia (SAA) was investigated as a pretreatment method for corn stover. In this method, the feedstock
was soaked in aqueous ammonia over an extended period (10–60 d) at room temperature. It was done without agitation at atmospheric
pressure. SAA treatment removed 55–74% of the lignin, but retained nearly 100% of the glucan and 85% of the xylan. The xylan
remaining in the corn stover after SAA treatment was hydrolyzed along with the glucan by xylanase present in the Spezyme CP
enzyme. In the simultaneous saccharification and fermentation (SSF) test of SAA-treated corn stover, using S. cerevisiae (D5A), an ethanol yield of 73% of theoretical maximum was obtained on the basis of the glucan content in the treated corn stover.
The accumulation of xylose in the SSF appears to inhibit the cellulase activity on glucan hydrolysis, which limits the yield
of ethanol. In the simultaneous saccharification and co-fermentation (SSCF) test, using recombinant E. coli (KO11), both the glucan and xylose were effectively utilized, resulting in on overall ethanol yield of 77% based on the glucan
and xylan content of the substrate. When the SSCF process is used, the fact that the xylan fraction is retained during pretreatment
is a desirable feature since the overall bioconversion can be carried out in a single step without separate recovery of xylose
from the pretreatment liquid. 相似文献